jgrusewski 2c97e0436c fix(dqn): unstick eval Kelly cap — health-coupled warmup_floor never collapses to zero
The eval-mode policy was producing diverse Boltzmann picks (verified by the
new `val_dir_dist` HEALTH_DIAG line) but every active-direction pick (Long /
Short) was collapsing to `actual_dir = Flat` because the Kelly cap forced
`target_position = 0` at cold start.

Cluster run `train-multi-seed-ddrpr` epoch 0 made this unambiguous:
  val_dir_dist [short=0.0000 hold=0.1953 long=0.0001 flat=0.8047]

Boltzmann fired correctly (sum hold + flat ≈ 100% of bars, with Hold ~ 20% =
the share of bars where the policy explicitly picked Hold; the other 80%
were active-direction picks all rerouted to Flat by `target_position = 0`).

Root cause in `trade_physics.cuh::kelly_position_cap`:
  warmup_floor = clamp(conviction, 0, 1)            // ← can hit 0
  effective_kelly = maturity*kelly_f + (1-maturity)*warmup_floor
                  = 0 + 1*0 = 0   at cold start with low conviction
  cap = effective_kelly * max_position * safety = 0 → no exposure permitted

The `safety_multiplier` was already protected by a `health_safety = 0.5 + 0.5×h`
floor, but `warmup_floor` had no such floor. Catch-22: low conviction → cap=0 →
no trades → Kelly stats stay cold → conviction stays low → forever.

The same bootstrap-deadlock pattern as the IQN trunk SAXPY readiness gate
(commit f86353840), and the fix is structurally identical — apply a non-zero
adaptive floor sourced from the same training-stability signal:

  warmup_floor = max(conviction, health_floor)

where `health_floor = 0.5 + 0.5 × ISV[LEARNING_HEALTH]` is the same value the
caller already computes for `safety_multiplier`. Both signals are adaptive
and ISV-driven; no tuned constants. The floor only matters during cold start
— once `maturity → 1` after ≥10 trades the term drops out entirely.

Threaded through both `apply_kelly_cap` and `kelly_position_cap` signatures;
single caller in `unified_env_step_core` passes `health_safety` as the new
arg (already locally computed two lines above). Build clean at 11-warning
baseline.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-26 19:47:20 +02:00

Foxhunt

Production HFT trading system in Rust.

Architecture

The workspace contains 32 crates organized as follows:

Core Libraries (16)

Crate Purpose
trading_engine Order processing, FIX 4.4, IB TWS, SIMD, RDTSC timing
risk VaR, Kelly, circuit breakers, kill switches, compliance
risk-data Risk data types and shared structures
trading-data Trading data types
ml DQN Rainbow, PPO, TFT, Mamba2, ensemble inference
ml-data ML data types and feature definitions
data Market data ingestion and storage
backtesting Replay engine, strategy tester
adaptive-strategy Ensemble execution, microstructure analysis
common Shared types, resilience, error handling
storage S3 and local model storage
model_loader Model serialization and loading
market-data Market data feed handlers
database PostgreSQL access layer (SQLx)
config Configuration management
tli CLI commands and tooling

Services (8)

Service Purpose
backtesting_service gRPC backtesting service
broker_gateway_service FIX routing, broker connectivity
trading_service Core trading operations
ml_training_service Model training orchestration
data_acquisition_service Market data acquisition
trading_agent_service Autonomous trading agents
api_gateway gRPC API gateway with auth
web-gateway Axum REST + WebSocket gateway

Frontend

web-dashboard/ -- React 19 + TypeScript + Vite + TradingView charts.

Building

# Check compilation (no PostgreSQL required)
SQLX_OFFLINE=true cargo check --workspace

# Run tests for a specific crate
SQLX_OFFLINE=true cargo test -p <crate> --lib

# Clippy
SQLX_OFFLINE=true cargo clippy --workspace

ML Models

Four production model architectures on Candle v0.9.1 with CUDA:

  • DQN Rainbow -- Deep Q-Network with prioritized replay, dueling heads, noisy nets
  • PPO -- Proximal Policy Optimization with GAE and LSTM policies
  • TFT -- Temporal Fusion Transformer for multi-horizon forecasting
  • Mamba2 -- State space model for sequence prediction

Each model has a standalone trainer and a UnifiedTrainable adapter for the hyperopt pipeline.

Infrastructure

  • Git: Gitea at git.fxhnt.ai (Tailscale-only), Scaleway DEV1-S
  • Observability: OpenTelemetry OTLP (env OTEL_EXPORTER_OTLP_ENDPOINT)
  • Database: PostgreSQL with SQLx offline mode for CI

License

Proprietary. All rights reserved.

Description
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